Method and apparatus for decontaminating fluid with delayed filtering



June 1970 M. R. ESTABRQOK 3,515,507

METHOD AND APPARATUS FOR DECONTAMINATING FLUID WITH DELAYED FILTERING' Filed Aug. 6, 1968 1:: me Q 17 c5152" Q6roo&

by 4J,W, WM 4 @M United States Patent 3,515,507 METHOD AND APPARATUS FOR DECON- TAMINATING FLUID WITH DELAYED FILTERING Mark R. Estabrook, Rockford, Ill., assignor to Barnes Drill Co., Rockford, Ill., a corporation of Illinois Filed Aug. 6, 1968, Ser. No. 750,567 Int. Cl. D06f 43/02, 39/10; B01d 37/00 US. Cl. 8158 Claims ABSTRACT OF THE DISCLOSURE A drycleaning and fluid decontamination apparatus and method wherein fluid initially is circulated from a reservoir through a hydroclone separator, then through a washer and a batch of articles to be cleaned, and then back to the reservoir for recirculation. After the separator has cleaned the fluid (and the batch) for a timed interval, a timer starts a pump which directs the output of the hydroclone through final cleaners in the form of filter and chemical cartridges for the remainder of the cycle, the clean fluid from the final cleaners passing through the washer and back to the reservoir.

BACKGROUND OF THE INVENTION This invention relates generally to the cleaning or decontamination of fluid in an apparatus in which fluid is circulated repeatedly through a work station, picks up contamination in the work station, and is cleaned prior to recirculation, and relates specifically to the initial cleaning of fluid with a hydroclone separator for removing larger solid particles and the finer cleaning of the fluid with one or more final cleaners, preferably in cartridge form and including at least one filter for collecting solid particles that have been passed by the hydroclone.

The invention has particular reference to a drycleaning apparatus in which the work station is a so-called washer where drycleaning fluid or solvent is passed through a batch of articles to be cleaned, and is circulated through the decontaminating portion of the apparatus for cleaning of the fluid after each pass through the washer and preparatory to recirculation through the latter. Filter cleaners have been used in this environment, along with chemical cleaners for removing dissolved contaminants, but the limited life of the cleaners due to clogging by collected solids has been a problem in some operations, making the operating cost somewhat higher and requiring more frequent attention from the operator than had been anticipated.

SUMMARY OF THE INVENTION The primary object of the invention is to provide a new and improved method and apparatus for decontaminating such fluid while protecting the final cleaner or cleaners from exposure to the bulk of larger solid particles circulating in the system, and particularly the initial load of solid particles removed from the work station and partially passing through the hydroclone when a cycle is initiated. More specifically, the invention utilizes'the hydroclone alone for removel of the initial load of contamination, subjects the fluid and the work station to a preselected interval of operation with the hydroclone alone so that repeated treatment of the fluid by the hydroclone substantially eliminates larger particles from the system, and then changes the flow from the hydroclone to pass through the final cleaners for a selected period constituting the remainder of the cleaning cycle. The invention also resides in the novel arrangement of the components of the apparatus for achieving the foregoing ends, and in the use of a pump initially as a blocking valve element Patented June 2, 1970 for routing fluid along its initial route and then forcing the fluid through the final cleaners during the remaining period of the cycle.

Other objects and advantages will become apparent from the following detailed description taken in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING The single figure is a partially schematic and fragmen tary side elevational view showing the primary components of a drycleaning and decontaminating apparatus embodying the novel features of the present invention and capable of practicing the steps thereof.

DETAILED DESCRIPTION As shown in the drawing for purposes of illustration, the invention is embodied in a cleaning apparatus for circulating fluid through a work station 10 such as a conventional drycleaner, hereafter called the washer, and decontaminating the fluid after passage through the washer by passing the fluid first through a hydroclone separator 11 for removal of larger solid contamination particles and then through one or more final cleaning elements for finer cleaning and polishing of the fluid before it is recycled through the washer. Herein, the final cleaning elements are arranged in a bank 12 of cartridges including two cartridges 13 of filter paper for straining out solid particles passed by the hydroclone, and also one chemical cartridge 14 for removing dissolved contaminants such as grease and dyes.

Hydroclones suitable for use with the invention are known in the art, the illustrative hydrochlone 11 having a conical treating chamber in a body 15 into which dirty fluid from a reservoir 17 is introduced by a centrifugal pump 18 through an inlet pipe 19, herein into a cylindrical extension 20 on the larger end of the body 15, to create a vortical flow of fluid toward the smaller end of the chamber. An underflow outlet at 21 opens through an inverted subcone at 22 into an underflow chamber shown at 23, this chamber being connected by a pipe 24 to the inlet 25 of an underflow pot 27. In a manner well known in the art, the hydroclone separates solid particles from the fluid and produces a reverse flow of clean fluid upwardly toward the larger end of the conical chamber and out through an outlet pipe 28. The separated solid particles pass downwardly through the underflow chamber 23 to the underflow pot 27 and preferably are collected in a removable filter bag (not shown), the accompanying fluid being drained through a pipe 29 back to the fluid reservoir 17 of the apparatus.

Although hydroclones have a relatively high elfectiveness in the removal of solids from fluid, a small percentage of the total solid contamination passes through the hydroclone 11, particularly particles in the smaller size ranges and larger particles when the concentration of contamination is high. Such contamination leaves the hydroclone with the clean" fluid in the pipe 28, and eventually is removed by the final cleaners 13 and 14. The filter cartridges 13 have papers capable of collecting virtually all particles above a selected size so that the flow out of the filters is of closely controlled cleanliness with respect to the size of any entrained solid particles. The chemical cartridge 14 has a chemical bed such as activated charcoal capable of removing dissolved contaminants from the flow through the bed, and is included for removal of free dyes from fabrics in the work chamber and other soluble contamination.

It will be seen in the drawing that the cartridge bank 12 is fed by a single branch 30 from the outlet pipe 28, and that the three cartridges are connected in parallel between this branch and a pipe 31 leading to the washer 10. A manifold 32 divides the output of the hydroclone 11 into three flows which enter the outer portions of the respective cartridges, pass through the paper or chemical therein, and then exit through center passages 33 in the cartridges connected through three outlets 34 to the pipe 31. Thus, only part of the output flow passes through each cartridge, and all of the flows are combined to pass through the washer. It has been found that this division is practical in service use, and that the repeated cycling of the fluid through the system results in satisfactory filtering and chemical treatment of the whole body of fluid circulating in the apparatus.

After passing through the washer and a batch of articles therein, the fluid returns to the reservoir 17 through a pipe 35 for recycling through the decontaminating apparatus by the pump 18. Initially, the fluid picks up a substantial amount of contamination during each pass through the washer, but the amount becomes progressively smaller as the operation continues, until finally the articles attain the desired degree of cleanliness and the operation may be terminated. This preferably is set up on a timed cycle which experience indicates is long enough to accomplish the desired result.

The service life of the filter cartridges 13 depends upon the concentration of solids in the hydroclone output, the resultant rate of build-up of solids in cakes on the outer sides of the filter papers, and the clogging of the pores of the paper by the solids. Since part of the hydroclone output also passes through the charcoal cartridge 14, this cartridge also is subject to clogging by accumulated solids. It will be evident that replacement of cartridges is a substantial factor in the operating cost of the apparatus and, in a commercial drycleaning establishment, this is a primary area of concern, both as to cost of cartridges and as to labor and down time required for servicing of the apparatus.

In accordance with the present invention, the initial, heavily contaminated fluid passed through the washer 10 and then through the hydroclone 11 is by-passed around the final cleaners 13 and 14 until the degree of solid contamination has been reduced substantially by the normal cleaning action of the hydroclone, the fluid being recirculated through the system for a selected period of time constituting the initial portion of the cleaning cycle. Then, after most of the solids have been removed from the batch of articles being cleaned, and also from the circulating fluid, the flow is changed to pass from the hydroclone through the final cleaners for finer cleaning before passing through the washer to complete the cleaning of the articles. In this manner, clogging of the final cleaners by the greater concentration of solids in the initial flow is avoided, while the full cycle results in the same overall cleaning effectiveness that would be obtained with final cleaning for the full cycle. Accordingly, there is a significant reduction in the loading, and rate of clogging, of the final cleaners, with increased service life and correspondingly reduced operating costs.

In this instance, the flow through the final cleaners 13 and 14 is controlled by a centrifugal pump 38 interposed in the branch line 30 between the outlet line 28 and the manifold 32, and a restriction 39 in the line 31, which is a by-pass line from the line 28 around the bank 12. During initial operation, the centrifugal pump 38 is inoperative, and serves as a closed valve in the line to prevent any appreciable flow to and through the final cleaners. After the selected time period for such by-passed flow, the pump is activated to draw fluid from the outlet line and force the fluid through the line 30 and the final cleaners under sufficient pressure for the final cleaning operation. During the remaining portion of the cycle, the pump 38 and the restriction 39 cooperate to prevent any appreciable flow through the by-pass line 31 around the bank.

To control the operation of the system, a motor 40 is provided to drive the main pump 18 constantly through out the operating cycle, the motor being started by a manually operable switch 41 for energizing a solenoid 4 42 across power lines 43 and 44. The solenoid controls four switches 45 which, when closed, complete a holding circuit through a line 47 around the start switch 41, and also connect the motor windings across the power lines.

When closed, the start switch 41 also completes an energizing circuit through a timer 48 to start the latter timing the initial part of the drycleaning cycle during which the fluid is by-passed around the final cleaners 13 and 14. The timer controls a solenoid 49 which initially is deenergized because the timer switch 50 is open, and the solenoid controls three switches 51 which, when open, maintain the pump 38 inoperative by maintaining the pump motor 52 in deenergized condition. Thus, the timer begins timing the interval for initial operation, and fluid is circulated through the system for removal of contamination from the washer 10, removal of solids from the fluid by the hydroclone 11, and return of the fluid directly back through the washer.

Assuming a total cycle on the order of 2530 minutes, the initial cycle may be on the order of 8-10 minutes, an interval long enough for removal of the bulk of solids from the batch of articles being cleaned and from the fluid itself. After the timer 48 times out, that is, at the end of the selected interval, the switch 50 is closed in the circuit of the solenoid 49 which closes the switches 51 to start the motor 52 and initiate the changed flow along the path including the branch 30, the final cleaners 13 and 14, the lines 34 to the line 31, and thence to the washer. For the remainder of the operating cycle, the output of the hydroclone is routed through the bank of final cleaners and thus is filtered and chemically treated to remove fine solids, dye and grease before being returned through the washer. The final portion of the cycle preferably is timed by a second timer (not shown) for opening a switch 53 for stopping the cycle and both pump motors 40 and 52 of the apparatus. Of course, the end of the cycle also may be controlled manually, for example, upon attainment of a preselected degree of clarity of the fluid.

With the foregoing arrangement, full advantage is taken of the capabilities of the apparatus without subjecting the final cleaners 13 and 14 to the heavy but progressively decreasing, full concentration of solids during the early part of a cycle. By deferring use of the final cleaners temporarily, the hydroclone is used to protect the cartridges and increase their service life to a significant eXtent.

I claim as my invention:

1. The method of removing contamination from batches of articles contained in a work station with a circulating flow of cleaning fluid, and cleaning the fluid during circulation with a hydroclone separator for removing solids and with final cleaning elements including a filter for polishing the fluid output of said separator, said method comprising the steps of, initiating the flow of fluid through said work station to remove contamination from the articles therein and passing the fluid from the work station through said separator for removal of solids, returning fluid from said separator through said work station around said elements to avoid exposure of the elements to the fluid during the early portion of the cleaning of articles, circulating the fluid through said station and said separator until most of the larger solid contamination in the station and in the fluid has been removed by repeated passage of the fluid through the separator, then changing the flow from said separator to pass through said elements before passing through said station thereby to subject the fluid to the polishing and final cleaning action of said elements, and maintaining the changed flow until both the articles and the fluid have 'been cleaned by repetitive passage of fluid through said elements.

2. The method defined in claim 1 in which said steps are performed over a preselected period of time, and the initial circulation of fluid through said separator and around the said elements is maintained for a timed initial portion of said period and the changed circulation is maintained for a timed remainder of said period.

3. The method of operating an apparatus having a Work station containing contamination, a reservoir of fluid, a hydroclone separator, a final cleaning bank including at least one filter, and a pump for circulating fluid from the reservoir through the apparatus to pick up contamination at said work station and to be cleaned for recirculation by said separator and said bank, said method comprising the steps of, initiating a flow of fluid from said reservoir through said work station to remove contamination therefrom, then through said separator for removal of solid contamination, and then by-passing said bank back through said work station; maintaining the initial flow until the bulk of larger solid contaminations has been removed from the work station by said fluid and from the fluid by said separator; changing the flow from said separator to pass through said bank for final cleaning of the fluid prior to passage thereof through said station, thereby to improve the cleaning of the fluid and the station during the changed flow; and terminating the flow through said station after an interval of operation with said changed flow.

4. Apparatus for cleaning batches of articles contained in a work station with a circulating flow of cleaning fluid, said apparatus having, in combination, a hydroclone separator, a final cleaning bank including at least one filter element capable of removing solid particles passed by said separator, a pump for circulating fluid through said apparatus and to and from the work station, a first line from said separator to said bank, a second line from said bank for delivering fluid to said work station, a third line from said separator around said bank for by-passing fluid from the separator directly to said station, first means operable upon initiation of a cleaning cycle to direct the flow from said separator through said third line and thence through said station for return to said separator whereby the initial cleaning of a batch of articles is accomplished with fluid that by-passes said bank and the latter is protected against exposure to the bulk of the particles that initially pass the separator, and second means operable after a preselected amount of such initial cleaning to direct the flow from said separator through said bank and thence through said station for return to said separator thereby to activate said bank for final cleaning of the articles and the fluid during the remainder of a cycle only after particles have been removed by said separator for said preselected amount of time.

5. Apparatus as defined in claim 4 in which said first means comprises a pump interposed between said separator and said bank and normally inoperative, thereby to block any appreciable flow from said separator through said bank, and said second means includes a timer for initiating operation of said pump to force fluid from said separator through said bank after expiration of a preselected time interval.

References Cited UNITED STATES PATENTS 2,044,096 6/ 1936 Moran 6818 X 2,075,010 3/ 1937 Angelus et a1. 68-18 3,291,562 12/1966 Anderson 8158 X 3,421,835 1/1969 McCarty 8-158 WILLIAM I. PRICE, Primary Examiner US. Cl. X.R. 

